Previous owners had carpet removed, new flooring installed, and there are huge gaps around the stone fireplace hearth. Not only is this unsightly, the floor is literally open to the crawlspace under the house. This puts out the welcome mat to all kinds of creepy critters, especially ants. LOTS of ants. Because the gaps are so wide, uneven, and deep, I'm at a loss as to how to fill/block them. Replacing the hearth is not an option. Help!!